Use of metal deactivator in fatty materials



2,921,856 USE OF METAL DEACTIVATOR IN FATTY MATERIALS Robert H. Rosenwald, Western Springs, 111., assignor, by

mesne assignments, to Universal Oil Products Company, Des Plaines, 11]., a corporation of Delaware Application November 13, 1956 Serial No. 621,537

8 Claims. (Cl. 99-163) No Drawing.

metal'constituents contained in the fatty material. The

edible fats and oils generally are of animal, vegetable or mineral origin. Typical representatives' of these fats and oils include linseed oil, menhaden oil, cod liver oil, castor oil, olive oil, rapeseed oil, coconut oil, palm oil, corn oil, sesame oil, peanut oil, babassu oil, butter, fat, lard, beef tallow, etc., as well as the hydrogenated oils. It is understood that other oils and fats may be treated within the scope of the present invention, including oils and fats which have previously been subjected to various treatments, such as blowing with air, hydrogenation, heat treatment, etc.

The compounds of the present invention which serve to deactivate the catalytic effect of metals are referred to as metal deactivators. These metal deactivators act 'on the metals present in the fatty material. The metal deactivators are distinguished from other additives gen- 'erally added to fatty materials for various purposes. For

example, an antioxidant is added to edible fats and oils in order to retard the development of rancidity therein. The metal deactivator will not substantially suppress rancidity development of edible fats and oils in the absence of metals, and the antioxidant will not suppress the catalytic effect of metals in the edible fats and oils to any considerable extent. In some cases the metal deactivator Will prevent color formation due to a reaction of a metal with an antioxidant as is the case with iron and propyl gallate.

In one embodiment the present invention relates to a method of stabilizing a fatty material against oxidative deterioration catalyzed by metal which comprises incorporating in said fatty material an ester of phosphoric acid containing at least 8 carbon atoms in the ester group.

In a specific embodiment the present invention relates to a method of stabilizing lard against oxidative deterioration catalyzed by a metal, which comprises incorporating in said lard from about 0.0001% to about 0.5% by weight of lauryl diacid phosphate.

The novel metal deactivator of the present invention may be illustrated by the following general formula:

8 carbon atoms. The hydrocarbon group of at least 8 carbon atoms, and preferably of from 8 to about 20 carbon atoms, is selected from alkyl, alkenyl, cycloalkyl,

2,921,856 Patented Jan. 19, 1960 aryl, alkaryl, or aralkyl. In some cases, the hydrocarbo group may be substituted with a radical containing oxygen, nitrogen, sulfur and/or phosphorus.

Referring to the above general formula, whereR is hydrogen, the preferred metal deactivator will comprise an alkyl diacid phosphate, the alkyl group containing at least 8 carbon atoms. Illustrative compounds in this class include octyl diacid phosphate, nonyl diacid phosphate, decyl diacid phosphate, undecyl diacid phosphate, dodecyl diacid phosphate, tridecyl diacid phosphate, tetradecyl diacid phosphate, pentadecyl diacid phosphate, hexadecyl diacid phosphate, heptadecyl diacid phosphate, octadecyl diacid phosphate, nonadecyl diacid phosphate, eicosyl diacid phosphate, etc. Conveniently, these esters or anhydrides are formed from fattyacids and thus include capryloyl diacid phosphate, caproyl diacid phosphate, lauroyl diacid phosphate, myristoyl diacid phosphate, palmitoyl diacid phosphate, stearoyl diacid phosphate, etc.

Where R' is an alkenyl group of at least 8 carbon atoms, the metal deactivator includes compounds as octenyl diacid phosphate, nonenyl diacid phosphate, decenyl diacid phosphate, undecenyl diacid phosphate, dodecenyl diacid phosphate, tridecenyl diacid phosphate, tetradecenyl diacid phosphate, pentadecenyl diacid phosphate, hexadecenyl diacid phosphate, heptadecenyl diacid phosphate, octadecenyl diacid phosphate, nonadecenyl diacid phosphate, eicosenyl diacid phosphate, etc. Here again, the ester is conveniently prepared from fatty acids and includes compounds as oleoyl diacid phosphate, recinoleoyl diacid phosphate, linoleoyl diacid phosphate, eleostearoyl diacid phosphate, etc.

Where R in the above general formula is a cycloalkyl group of at least 8 carbon atoms, the metal deactivator may comprise compounds as trimethylcyclopentyl diacid phosphate, tetramethylcyclopentyl diacid phosphate, diethylcyclopentyl diacid phosphate, triethylcyclopentyl diacid phosphate, tetraethylcyclopentyl diacid phosphate, propylcyclopentyl diacid phosphate, dipropylcyclopentyl diacid phosphate, tetrapropylcyclopentyl diacid phosphate, butylcyclopentyl diacid phosphate, dibutylcyclo pentyl diacid phosphate, tributylcyclopentyl diacid phosphate, amylcyclopentyl diacid phosphate, diamylcyclopentyl diacid phosphate, triamylcyclopentyl diacid phosphate, hexylcyclopentyl diacid phosphate, dihexylcyclopentyl diacid phosphate, heptylcyclopentyl diacid phos phate, diheptylcyclopentyl diacid phosphate, octylcyclopentyl diacid phosphate, dioctylcyclopentyl diacid phosphate, etc., methylethylcyclopentyl diacid phosphate, methylpropylcyclopentyl diacid phosphate, methylbutylcyclopentyl diacid phosphate, methylamylcyclopentyl diacid phosphate, methylhexylcyclopentyl diacid phosphate, etc., ethylpropylcyc'lopentyl diacid phosphate, ethylbutylcyclopentyl diacid phosphate, ethylamylcyclopentyl diacid phosphate, ethylhexylcyclopentyl diacid phosphate, propylbutylcyclopentyl diacid phosphate, propylamylcyclopentyl diacid phosphate, propylhexylcyclopentyl diacid phosphate, butylamylcyclopentyl diacid phosphate, butylhexylcyclopentyl diacid phosphate, etc., dimethylcyclohexyl diacid phosphate, trimethylcyclohexyl diacid phosphate, tetramethylcyclohexyl diacid phosphate, ethylcyclohexyl diacid phosphate, diethylcyclohexyl diacid phosphate, triethylcyclohexyl diacid phosphate, tetraethylcyclohexyl diacid phosphate, propylcyclohexyl diacid phosphate, dipropylcyclohexyl diacid phosphate, tripropylcyclohexyl diacid phosphate, tetrapropylcyclohexyl diacid phosphate, butylcyclohexyl diacid phosphate, dibutylcyclohexyl diacid phosphate, tributylcyclohexyl diacid phosphate, amylcyclohexyl diacid phosphate, diamylcyclohexyl diacid phosphate, triamylcyclohexyl diacid phosphate, hexylcyclohexyl diacid phosphate, dihexylcyclohexyl diacid phosphate, hepty1- .hexyl diacid phosphate,

diacid phosphate, methylpropylcyclohexyl diacid phosphate, methylbutylcyclohexyl diacid phosphate, methyl- "amylcyclohexyl diacid phosphate, methylhexylcyclohexyl diacid phosphate, methylheptylcyclohexyl diacid phosmonoacid phosphate butyltetradecyl monoacid phosphate, methyloctylcyclohexyl diacid phosphate, etc.,

ethylpropylcyclohexyl diacid phosphate, ethylbutylcycloethylamylcyclohexyl 7 diacid phosphate, ethylhexylcyclohexyl diacid phosphate, propylbutylcyclohexyl diacid phosphate, propylamylcyclohexyl diacid phosphate, propylhexylcyclohexyl diacid phosphate, etc., butylamylcyclohexyl diacid phosphate, butylhexylcyclohexyl diacid phosphate, amylhexylcyclohexyl diacid phosphate, 'hexylheptylcyclohexyl diacid phosphate, etc. Also included in the'cycloalkyl grouping phosphate, cyclopentylamyl' diacid phosphate, cyclohexylethyl diacid phosphate, .cyclohexylpropyl diacid phosphate, cyclohexylbutyl diacid phosphate, cyclohexylamyl diacid phosphate, cyclohexylhexyl diacid phosphate,

'eyelohexylheptyl diacid phosphate, cyclohexyloctyl diacid phosphate, etc.

Referring again to the above general formula, where R is a hydrocarbon group, the preferred metal'deactivator comprises a dialkyl monoacid phosphate, at least one ofthe alkyl groups containing at least 8 carbon atoms. In one embodiment, it is preferred that both alkyl groups are the same and that each contains at least 8 carbon atoms. These alkyl groups are selected from those specifically set forth hereinabove. Illustrative compounds in this class include dioctyl monoacid phosphate, dinonyl monoacid phosphate, didecyl monoacid phosphate,.diundecy1monoacid phosphate, didodecyl monoacid phosphate, ditridecyl monoacid phosphate, ditetradecyl monoacid phosphate, dipentadecyl monoacid phosphate, dihexadecyl monoacid phosphate, diheptadecyl monoacid phosphate, dioctadecyl monoacid phosphate, dinonadecyl monoacid phosphate, dieicosyl monoacid phosphate, etc. In another embodiment the alkyl groups may be different, but at least one of the alkyl groups must contain at least 8 carbon atoms. Illustrative compoundsrin this class include methyloctyl monoacid phosphate, ethyloctyl monoacid phosphate, propyloctyl monoacid phosphate, butyloctyl monoacid phosphate, amyloctyl monoacid phosphate,.,hexyloctyl monoacid phosphate,. heptyloctyl monoacid phosphate, etc., methyl- 'nonyl monoacid phosphate, ethylnonyl monoacid phosphate, propylnonyl monoacid phosphate, butylnonyl monoacid phosphate, amylnonyl monoacid phosphate, hexylnonyl monoacid phosphate, heptylnonyl monoacid phosphate, etc., methyldecyl monoacid phosphate, ethyl-' decyl monoacid phosphate, propyldecyl monoacid phosphate, butyldecyl monoacid phosphate, amyldecyl monoacid phosphate, hexyldecyl monoacid phosphate, heptyldecyl monoacid phosphate, etc., methylundecyl monoacid phosphate, ethylundecyl monoacid phosphate, propylundecylmonoacid phosphate, butylundecyl monoacid phosphate, amylundecyl monoacid phosphate, hexylundecyl monoacid phosphate, heptylundecyl monoacid phosphate, etc., methyldodecyl monoacid, phosphate, ethyldodecyl monoacid phosphate, propyldodecyl monoacid phosphate, butyldodecyl monoacid phosphate, amyldodecyl monoacid phosphate, hexyldodecyl monoacid phosphate, heptyldodecyl monoacid phosphate, etc., methyltridecyl monoacid phosphate, ethyltridecyl monoacid phosphate, propyltridecyl monoacidphosphate, butyltridecyl monoacid phosphate, amyltridecyl mor oacid phosphate, hexyltridecyl monoacid phosphate, heptyltridecyl monoacid phosphate, etc., methyltetradecyl monoacid phosphate, ethyltetradecyl monoacid phosphate, propyltetradecyl are cycloalkyl alkyl esters including, for example, cyclepentylpropyl diacid phosphate, cyclopentylbutyl diacid phate, amyltetradecyl monoacid phosphate, hexyltetradecyl monoacid phosphate, heptyltetradecyl monoacid phosphate, etc.

The specific compounds in the previous paragraph comprise those in which R and 'R' both are alkyl groups, at least one of which contains at least 8 carbon atoms. It is understood that, in another embodiment, one or both of these groups may be selected from the other hydrocarbon groups specifically set forth in the description of the monoalkyl diacid phosphates.

In still another embodiment of the invention, the metal deactivator maycomprise an ester of a 'pyrophosphate, the ester containing at least one hydrocarbon group having at least 8 carbon atoms. The hydrocarbon group is selected from the specific substituents hereinbefore set forth in the description of the diacid and monoacid phosphates. r r

As hereinbefore set forth, it is essential that at least one of the ester groups contains at least 8 carbon atoms. This is necessary in order that the ester is readily soluble in the fatty material being stabilized. Unless the metal deactivator is sufliciently soluble in the fatty material,,the metal deactivator will precipitate out of solution and will not serve to deactivate the metal and to prevent the metal from catalyzing 'oxidative deterioration of the fatty material.

It is understood that the various compounds which may be utilized in accordance with the present invention are not necessarily equivalent in the same or different fatty material. When used in edible fatty materials, the metal deactivator must be non-toxic and must not impart undesired color and odor to the fatty'material.

On the other hand, when used in fatty materials which are not edible but are used, for example, as grease, lubricant, etc., the metal deactivator need not necessarily be non-toxic. I i

As hereinbefore set forth, the metal deactivator of the present invention generally will be used in conjunction with other, additives. In the stabilization of-fatty materials, a preferred antioxidant comprises butylated hydroxyanisole. I Another preferred antioxidant comprises a mixture of butylated hydroxyanisole and butylated hydroxytoluene. Other antioxidants include nordihydroguaiaretic acid (N.D.G.A.), gum guaiac, propyl gallate, lauryl thiodipropionate, various alkylated phenolic compounds including butylated hydroxytoluene (2,6 -ditertiary-butyl -4 -methylphenol), etc. Still other antioxidants include hydroquinone, 2,4-dimethyl-6-tertiarybutylphenol, coumaran, N,N' -diphenyl-p-phenylene diamine, etc.

The antioxidant generally is utilized in a concentration of below about 1% by weight and preferably from about 0.0001% to about 1% by weight. As hereinbefore set forth, the metal deactivator is utilized in'small concentrations and thus'may range from about 0.0001% to about0.5'% by weight of the substrate. The metal deactivator may be marketed as such or dissolved in a suitable solvent which is not reactive therewith. In some cases, when a solvent is used for the antioxidant or other additive, the same solvent may be used for the metal deactivator, and thus the two or more compounds, when desired, may be prepared as a mixture in a suitable solvent and the product marketed as a single commodity of a two-fold purpose.

It is understood that the metal deactivator of the present invention also may be employed along with other synergists or metal deactivators. Thus, the metal deactivator of the present invention may be utilized along with the oxidation inhibitor and citric acid, esters of citric acid, other polycarboxylic acid derivatives, etc. The combined use of these materials in many cases gives a greater stability than is obtained by using these compounds iniduau a 2,2 dimethyl 6 tertiary-butyl-S-hydroxy Thefollowing examples are introduced to illustrate further the novelty and utility of the present invention but not with the intention of unduly limiting the same.

Example I The lard used in this example had a normal stability period of four hours as determined by the Active Oxygen method. This method is a standard test for determining stability of lard. In general, this test comprises bubbling air through a sample of the lard and periodically determining the peroxide number. The results are reported as the number of hours required to reach a peroxide number of 20. I

The antioxidant composition of this example was incorporated in a sample of the lard in a concenration of 0.01% by weight of butylated hydroxyanisole and 0.0043% by weight of propyl gallate. The antioxidant composition was prepared as a solution in propylene glycol monolaurate. The addition of the antioxidant composition to the lard served to increase the stability period of the lard from 4 hours to 66.5 hours.

In order to illustrate the effect of metal, iron was incorporated in another sample of the lard in a concentration of one part per million of iron. The iron Was incorporated in the lard in the form of a stearate. Upon the addition of the mixed antioxidant in the same concentration as above set forth to the lard containing iron,

the stability period of the lard was 22 hours. This illustrates that the antioxidant composition does not serve to deactivate the catalytic etfect of the metal.

Example II The metal deactivator of this example is lauryl diacid phosphate. It was prepared as a solution in propylene glycol monolaurate along with butylated hydroxyanisole and butylated hydroxytoluene. When incorporated in a sample of lard containing one part per million of iron in a concentration of 0.0022% by weight of lauryl diacid phosphate, 0.01% by weight butylated hydroxyanisole and 0.0043% by weight of propyl gallate, the stability period of the lard was 71.5 hours. The lauryl diacid phosphate was readily soluble in the lard and served to completely deactivate the catalytic effect of the metal.

Example III The metal deactivator of this example is decyl diacid phosphate. It was prepared as a solution in propylene glycol monolaurate along with butylated hydroxyanisole and propyl gallate. When incorporated in another sample of the l-ard containing one part per million of iron in a concentration of 00.22% by weight of decyl diacid phosphate, 0.01% by weight of butylated hydroxyanisole and 0.0043% by weight of propyl gallate, the stability period of the lard was 65 hours. It will be noted that the decyl diacid phosphate served to complately deactivate the catalytic effect of the metal.

Example IV The metal deactivator of this example was oleyl diacid phosphate. It was prepared as a solution in propylene glycol monolaurate along with butylated hydroxyanisole and propyl gallate. When incorporated in another sample of the lard containing one part per million of iron in a concentration of 0.0022% by weight of oleyl diacid phosphate, 0.01% by weight of butylated hydroxyanisole and 0.0043% by weight of propyl gallate, the stability period of the lard was 65 hours. Here again, it will be noted that the metal deactivator of the present invention served to completely deactivate the catalytic eifect of the metal.

Example V metal.

weight of butylated hydroxyanisole and 0.010 5% by weight of butylated hydroxytoluene, the stability period of the lard was increased from 4 to 52.5 hours.

When this antioxidant composition was incorporated in the same concentration in another sample of the lard containing one part per million of iron, the stability period of the lard was reduced to 26 hours. Here again, it will be noted that the antioxidant composition did not serve to deactivate the catalytic effect of the metal.

Example VI The metal deactivator of this example is lauryl diacid phosphate and was prepared as a solution in Wesson oil along with butylated hydroxyanisole and butylated hydroxytoluene. When incorporated in another sample of the lard containing one part per million of iron in a concentration of 0.0024% by weight of lauryl diacid phosphate, 0.0086% by weight of butylated hydroxyanisole and 0.0105% by weight of butylated hydroxytoluene, the stability period of the lard was 58 hours. It will be noted that the metal deactivator served to completley deactivate the catalytic efiect of the metal.

Example VII The metal deactivator of this example is tridecyl diacid phosphate. It was prepared as a solution in Wesson oil along with butylated hydroxyanisole and butylated hydroxytoluene. When incorporated in another sample of the lard containing one part per million of iron in a concentration of 0.0024% by weight of didecyl diacid phosphate, 0.0086% by weight of butylated hydroxyanisole and 0.0105% by weight of butylated hydroxytoluene, the stability period of the lard was 55 hours. Here again, it will be noted that the metal deactivator served to completely deactivate the catalytic effect of the Example VIII The metal deactivator of this example is decyl diacid phosphate. It was prepared as a solution in Wesson oil along with butylated hydroxyanisole and butylated hydroxytoluene. When incorporated in another sample of the lard containing one part per million of iron in a concentration of 0.0024% by weight of decyl diacid phosphate, 0.0086% by weight of butylated hydroxyanisole and 0.0105% by weight of butylated hydroxytoluene, the stability period of the lard was 55 hours. Here again, it will be noted that the metal deactivator served to completely deactivate the catalytic eflect of the metal.

I claim as my invention:

1. The method of stabilizing a fatty material containing a metal constituent which normally catalyzes deterioration of said fatty material, which comprises incorporating in said fatty material an antioxidant comprising butylated hydroxyanisole and a metal deactivator comprising an ester of phosphoric acid containing at least 8 carbon atoms in the ester group, said ester being in a small but sufficient amount to deactivate the catalytic etfect of said metal const1tuent.

2. The method of stabilizing lard containing a metal constituent which normally catalyzes rancidity, which comprises incorporating in the lard an antioxidant comprising butylated hydroxyanisole and a metal deactivator comprising an ester of phosphoric acid containing at least 8 carbon atoms in the ester group, said ester being in a small but sufficient amount to deactivate the catalytic effect of said metal constituent.

3. Fatty material containing a metal constituent which normally catalyzes deterioration thereof and additionally containing an antioxidant comprising butylated hydroxyanisole and a metal deactivator comprising an ester of phosphoric acid containing from 8 to about 30 carbon atoms in the ester group, said ester being in a small but sufiicient amount to deactivate the catalytic effect of said metal constituent.

4. Lara containing an antioxidant m risi gbut 1ated 5; Lard containing from about 0.0001% to about 1% 0.0001% to about 0.5% by weight of lauryl diacid phosphate.

6. Lard containing from about 0.0001% to about 1% by weight of butylated 'hydroxyanisole and from about 0.0001% to about 0.5% by weight of o1ey1 diacid phosphate. r V

' 7. Lard containing from'about 0.0001% to about 1% by weight of butylated hydroxyanisole and from about 0.000'1% to about 1% by weight of decyl diacid phosphate.

by weightof butylated hydroxyanisole and from about 5 8 v 8. Lard containing from about 0.000196. to about 1% by weight of butylated hydroxyanisole and from about 0.0001% to about 1% by weight of tridecyl diacid phosphate. v

Re'ferences Cited in the file of this patent UNITED STATES PATENTS 2,648,608 Beadle et a1 Aug. 11, 1953 

1. THE METHOD OF STABILIZING A FATTY MATERIAL CONTAINING A METAL CONSTITUENT WHICH NORMALLY CATALYZES DETERIORATION OF SAID FATTY MATERIAL, WHICH COMPRISES INCORPORATING IN SAID FATTY MATERIAL AN ANTIOXIDANT COMPRISING BUTYLATED HYDROXYANISOLE AND A METAL DEACTIVATOR COMPRISING AN ESTER OF PHOSPHORIC ACID CONTAINING AT LEAST 8 CARBON ATOMS IN THE ESTER GROUP, SAID ESTER BEING IN A SMALL BUT SUFFICIENT AMOUNT TO DEACTIVATE THE CATALYTIC EFFECT OF SAID METAL CONSTITUENT. 